In dentistry, it is common to dispense different dental materials with a cartridge used in combination with a syringe. In many applications, the dental material is required to be mixed within the cartridge, such as in the use of amalgam, cement, or glass ionomer materials. Some dental capsules may come prepackaged or premixed. Additionally, some capsules are not able to be dispensed from the capsule directly. Many prepackaged capsules are limited in the volume of material that can be mixed because of the limited amount of component materials that are prepackaged, such as a volume of liquid. A first component of a material is usually placed within a cartridge or capsule and mixed with a liquid component in a mechanical mixer, such as an amalgamator, prior to dispensing. While mixing these dental materials, it is required to keep the first component, which is typically a powder, from entering the delivery portion of the cartridge or capsule. The delivery portion is usually a reduced diameter cannula having a lumen or small bore therein. Problems often occur in that an umixed portion of the first component will inadvertently enter the lumen and cause blockage. This prevents dispensing of the mixed dental material contained within the body of the cartridge. Material and time is often wasted in that the defective cartridge must be thrown away, and the process of mixing the dental material started over. This is inconvenient in that the patient must typically wait, after being prepared for application of the dental material, until the dentist can prepare another cartridge of dental material. Additionally, the dentist looses valuable productive time. Various methods have been used in an attempt to prevent unintentional blockage of the lumen with dental material before being mixed. Such solutions have been in the form of pins inserted within the lumen to prevent material unintentionally entering the lumen, and seals placed between the lumen and the interior body portion of a cartridge. However, these methods are often inconvenient to use and not completely reliable. One such cartridge is disclosed in U.S. Pat. No. 5,172,807 entitled "Cement Mixing Capsule" and issuing to Dragan et al on Dec. 22, 1992, which is herein incorporated by reference. Therein disclosed is a dental cartridge or capsule having a frangible seal placed between a nozzle and the body portion of the capsule to prevent unmixed cement from entering the nozzle. Another cartridge and dental syringe is disclosed in U.S. Pat. No. 5,306,147 entitled "Dental Syringe and Cartridge Therefor" issuing to Dragan et al on Apr. 26, 1994, which is herein incorporated by reference. While these prior devices and methods have proven useful, there is a need for a more reliable and easily manufactured dental cartridge for use with dental materials requiring mixing or requiring to be temporally separated from a cannula used for dispensing or applying the dental material.